The chemical-free devices are timely, given that the government's chemical regulator has suspended the use of several of the most popular insecticides because of the threat to public health.

Insects and pathogens that attack crops cost the industry millions of dollars each year. Industry and government spent more than $128 million managing fruit flies, one of the most devastating pests, between 2003 and 2008.

Paul De Barro, of the CSIRO's new Biosecurity Flagship, said the group's most advanced technology used microwaves to kill insects and their eggs inside crops such as apples, avocadoes, capsicums and zucchinis. Fruit or vegetables were exposed to microwaves as they moved through the machine on a conveyor belt.

The project leader, Mala Gamage, said the team was establishing the heating ranges required to kill different insects while maintaining the quality of the fruit or vegetable. ''Some of our heating protocols were very effective, and we were able to get 100 per cent mortality,'' Dr Gamage said.

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An initial trial to evaluate the technology on apples found the microwave treatment may also prolong the shelf life of the produce, a big advantage for sellers exporting their goods.

Dr De Barro said local producers needed other ways to disinfest their produce after harvest so they could continue selling to domestic and international markets that were pest-free zones.

''The big-picture view that we have is that you could put these microwave machines on a semi-trailer, take it to a packing shed and the product could move off the sorting tray and into the facility - it would be a mobile technology,'' said Dr De Barro.

The group is in the early stages of investigating several other chemical free-technologies, including cool plasma, which uses energised gas to inactivate fungi and bacteria on the surface of seeds, and high-pressure processing.

''Imagine a pre-packaged meal, ready to eat, that goes into a big pressure cylinder, where the pressure is raised to a point that kills the bugs,'' said Dr De Barro.

While farmers continue to spray crops before harvesting, CSIRO's technologies would replace the need for post-harvest insecticides.